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1.
Characterization of rco-1 of Neurospora crassa, a pleiotropic gene affecting growth and development that encodes a homolog of Tup1 of Saccharomyces cerevisiae. 总被引:2,自引:1,他引:1 下载免费PDF全文
C T Yamashiro D J Ebbole B U Lee R E Brown C Bourland L Madi C Yanofsky 《Molecular and cellular biology》1996,16(11):6218-6228
2.
mtDNA diversity in rhesus monkeys reveals overestimates of divergence time and paraphyly with neighboring species 总被引:4,自引:0,他引:4
Reconstructions of the human-African great ape phylogeny by using
mitochondrial DNA (mtDNA) have been subject to considerable debate. One
confounding factor may be the lack of data on intraspecific variation. To
test this hypothesis, we examined the effect of intraspecific mtDNA
diversity on the phylogenetic reconstruction of another Plio- Pleistocene
radiation of higher primates, the fascicularis group of macaque (Macaca)
monkey species. Fifteen endonucleases were used to identify 10 haplotypes
of 40-47 restriction sites in M. mulatta, which were compared with similar
data for the other members of this species group. Interpopulational,
intraspecific mtDNA diversity was large (0.5%- 4.5%), and estimates of
divergence time and branching order incorporating this variation were
substantially different from those based on single representatives of each
species. We conclude that intraspecific mtDNA diversity is substantial in
at least some primate species. Consequently, without prior information on
the extent of genetic diversity within a particular species, intraspecific
variation must be assessed and accounted for when reconstructing primate
phylogenies. Further, we question the reliability of hominoid mtDNA
phylogenies, based as they are on one or a few representatives of each
species, in an already depauperate superfamily of primates.
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3.
Rco-3, a Gene Involved in Glucose Transport and Conidiation in Neurospora Crassa 总被引:2,自引:0,他引:2 下载免费PDF全文
Macroconidiation in Neurospora crassa is influenced by a number of environmental cues, including the nutritional status of the growing organism. Conidia formation is normally observed when the fungus is exposed to air. However, carbon limitation can induce conidiation in mycelia submerged in an aerated liquid medium. A mutant was previously isolated that could conidiate in submerged culture without imposing nutrient limitation and the gene responsible for this phenotype (rco-3) has now been cloned. RCO3 exhibits sequence similarity to members of the sugar transporter gene superfamily, with greatest similarity to glucose transporters of yeast. Consistent with this structural similarity, we find that glucose transport activity is altered in the mutant. However, growth of the mutant in media containing alternate carbon sources does not suppress conidiation in submerged culture. The properties of the mutant suggest that RCO3 is required for expression of glucose transport activity, glucose regulation of gene expression, and general carbon repression of development. 相似文献
4.
Recurrent locus-specific mutation resulting from a cryptic ectopic insertion in Neurospora 下载免费PDF全文
New mutations are found among approximately 20% of progeny when one or both parents carry eas allele UCLA191 (eas(UCLA), easily wettable, hydrophobin-deficient, linkage group II). The mutations inactivate the wild-type allele of cya-8 (cytochrome aa3 deficient, linkage group VII), resulting in thin, "transparent" mycelial growth. Other eas alleles fail to produce cya-8 mutant progeny. The recurrent cya-8 mutations are attributed to repeat-induced point mutation (RIP) resulting from a duplicated copy of cya-8+ that was inserted ectopically at eas when the UCLA191 mutation occurred. As expected for RIP, eas(UCLA)-induced cya-8 mutations occur during nuclear proliferation prior to karyogamy. When only one parent is eas(UCLA), the new mutations arise exclusively in eas(UCLA) nuclei. Mutation of cya-8 is suppressed when a long unlinked duplication is present. Stable cya-8 mutations are effectively eliminated in crosses homozygous for rid, a recessive suppressor of RIP. The eas(UCLA) allele is associated with a long paracentric inversion. A discontinuity is present in eas(UCLA) DNA. The eas promoter is methylated in cya-8 progeny of eas(UCLA), presumably by the spreading of methylation beyond the adjoining RIP-inactivated duplication. These findings support a model in which an ectopic insertion that created a mutation at the target site acts as a locus-specific mutator via RIP. 相似文献
5.
Pheromones play important roles in female and male behaviour in the filamentous ascomycete fungi. To begin to explore the role of pheromones in mating, we have identified the genes encoding the sex pheromones of the heterothallic species Neurospora crassa. One gene, expressed exclusively in mat A strains, encodes a polypeptide containing multiple repeats of a putative pheromone sequence bordered by Kex2 processing sites. Strains of the opposite mating type, mat a, express a pheromone precursor gene whose polypeptide contains a C-terminal CAAX motif predicted to produce a mature pheromone with a C-terminal carboxy-methyl isoprenylated cysteine. The predicted sequences of the pheromones are remarkably similar to those encoded by other filamentous ascomycetes. The expression of the pheromone precursor genes is mating type specific and is under the control of the mating type locus. Furthermore, the genes are highly expressed in conidia and under conditions that favour sexual development. Both pheromone precursor genes are also regulated by the endogenous circadian clock in a time-of-day-specific fashion, supporting a role for the clock in mating. 相似文献
6.
The Aspergillus nidulans flbD gene encodes a protein with a Myb-like DNA-binding domain that is proposed to act in concert with other developmental regulators to control initiation of conidiophore development. We have identified a Neurospora crassa gene called rca-1 (regulator of conidiation in Aspergillus) based on its sequence similarity to flbD. We found that N. crassa rca-1 can complement the conidiation defect of an A. nidulans flbD mutant and that induced expression of rca-1 caused conidiation in submerged A. nidulans cultures just as was previously observed for overexpression of flbD. Thus, the N. crassa gene appears to be a functional homologue of A. nidulans flbD and this is the first demonstration of functional complementation of an A. nidulans sporulation defect using a gene from an evolutionarily distant fungus. However, deletion of the rca-1 gene in N. crassa had no major effect on growth rate, macroconidiation, microconidiation, or ascospore formation. The only phenotype displayed by the rca-1 mutant was straight or counterclockwise hyphal growth rather than the clockwise spiral growth observed for wild type. Thus, if rca-1 is involved in N. crassa development, its role is subtle or redundant. 相似文献
7.
Muma JB Lund A Siamudaala VM Munang'andu HM Munyeme M Matope G Nielsen K DJønne B Godfroid J Tryland M Skjerve E 《Journal of wildlife diseases》2010,46(4):1063-1069
One of the diseases of veterinary and public health importance affecting the Kafue lechwe (Kobus leche kafuensis) on the Kafue flats is brucellosis, for which only scant information is available. During the 2003 (October), 2004 (December), and 2008 (July-December) hunting seasons in the Kafue flats, we conducted a study to determine the seroprevalence of Brucella spp. in the Kafue lechwe and to evaluate serologic tests for detection of Brucella spp. antibodies in lechwe. The Rose Bengal Test (RBT), competitive enzyme-linked immunosorbent assay (cELISA), and fluorescence polarization assay (FPA) were used. A total of 121 Kafue lechwe were hunted for disease investigations in 2003, 2004, and 2008 in the Kafue Flat Game Management Area. Of these, 21.6%, (95% confidence interval [CI]: 14.2-29.1%) had detectable antibodies to Brucella spp. The Kafue lechwe in Lochnivar National Park had higher antibody results than those in Blue Lagoon National Park (odds ratio=3.0; 95% CI: 0.94-9.4). Infection levels were similar in females (21.6%) and males (21.7%). Results were similar among RBT, FPA, cELISA tests, suggesting that these could effectively be used in diagnosing brucellosis in the Kafue lechwe. Our study demonstrates the presence of Brucella infections in the Kafue lechwe in two national parks located in the Kafue flats and further highlights the suitability of serologic assays for testing the Kafue lechwe. Because the Kafue lechwe is the most hunted wildlife species in Zambia, hunters need to be informed of the public health risk of Brucella spp. infection. 相似文献
8.
9.
Susan DJ Chapple Anna M Crofts S Paul Shadbolt John McCafferty Michael R Dyson 《BMC biotechnology》2006,6(1):49-15
Background
A variety of approaches to understanding protein structure and function require production of recombinant protein. Mammalian based expression systems have advantages over bacterial systems for certain classes of protein but can be slower and more laborious. Thus the availability of a simple system for production and rapid screening of constructs or conditions for mammalian expression would be of great benefit. To this end we have coupled an efficient recombinant protein production system based on transient transfection in HEK-293 EBNA1 (HEK-293E) suspension cells with a dot blot method allowing pre-screening of proteins expressed in cells in a high throughput manner. 相似文献10.